For possible deployment in 2020, South Korea is developing supersonic anti-ship missiles, a report said Thursday. The move is apparently in line with an arms race among China and other countries in Northeast Asia to strengthen their ship-killing firepower.

Russia, China and Japan have developed or are developing supersonic anti-ship missiles that can travel faster than the speed of sound. High Mach numbers make them more survivable against shipboard defenses.

South Korea's supersonic anti-ship missiles would be able to travel at up to four times the speed of sound and have a range of 300-500 kilometers, Yonhap news agency said, citing military sources.

Russia's P-800 Onyx (Yakhont) is capable of traveling at up to 2.6 times the speed of sound and has a 300-kilometer range. The sea-skimming missile can be launched from land, sea, air and submarine, flying 15 meters above sea level to avoid radar and infrared detection as it approaches its target.

For decades, the two Koreas have been locked in a race to develop and produce various missiles, with North Korea taking the upper hand in extending the range of ballistic missiles. With its ballistic missile program restricted under a defense accord with the United States, South Korea has focused on guided and cruise systems.

On Tuesday, Yonhap reported that South Korea has completed the development of new tactical ship-to-ground guided missiles capable of destroying North Korean military equipment, missile bases and other key facilities.